How to Get Cron to Call in the Correct Paths

How to get CRON to call in the correct PATHs

I used /etc/crontab. I used vi and entered in the PATHs I needed into this file and ran it as root. The normal crontab overwrites PATHs that you have set up. A good tutorial on how to do this.

The systemwide cron file looks like this:

This has the username field, as used by /etc/crontab.
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file.
# This file also has a username field, that none of the other crontabs do.

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# m h dom mon dow user   command
42 6 * * *   root    run-parts --report /etc/cron.daily
47 6 * * 7   root    run-parts --report /etc/cron.weekly
52 6 1 * *   root    run-parts --report /etc/cron.monthly
01 01 * * 1-5 root python /path/to/file.py

Using Relative Paths in Crontab

After many trials and research, I discovered that the solution was using the HOME= variable, not the PATH= variable, like so:

SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=""
HOME=/var/www/html/crons

And then each of the lines would just look like:

*/2 * * * * root /usr/bin/php cronfile.php >> logs/cronfile_`date +\%Y\%m\%d`.log

Hope this helps someone else with the same issue I had in the future.

Bash: Prune find results using absolute paths

Note that the pattern match test applies to the whole file name,
starting from one of the start points named on the command line. It
would only make
sense to use an absolute path name here if the relevant start point is also an absolute path. This means that this command
will never match anything:

find bar -path /foo/bar/myfile -print

You need to use the absolute path as search base too, so exchange the first . (the starting point of the search) with the same absolute path you use for the -path arguments.

find /usr -path "/usr/src/linux*" -prune -o -path "/usr/inclu*" -prune -o -name "*.txt" -print

This will list all *.txt files but the content of any directory starting with /usr/src/linux* or /usr/inclu*.

Unable to run python script with shebang from /usr/local/bin

From the error:

bash: ./usr/local/bin/check_bios.py: No such file or directory

the cron job was looking for the check_bios.py script in the ./usr/local/bin path.

From that, I guessed that the cron job was:

? ? ? ? ? ./usr/local/bin/check_bios.py

where ? represents the time values (deliberately left them as ? since they weren't mentioned in the post, nor are they relevant to the issue).

I believe it should be:

? ? ? ? ? . /usr/local/bin/check_bios.py

Cron, execute bash script as root, but one part (Python script) as user

Well, if the dummy folders did get created, that means the sudo statements work, so i'd say theres a 99%+ chance that python was infact started.

I'm guessing the problem is that you havent specified the path for the python file, and your working directory likely isn't what you're expecting it to be.

change:

sudo -u user_name /usr/bin/python3 python_script.py --arg01 --arg02

to something like

sudo -u user_name /usr/bin/python3 /path/to/your/python_script.py --arg01 --arg02

then test.

If that didn't solve the problem , then enable some logging, change the line to:

sudo -u user_name /usr/bin/python3 /path/to/your/python_script.py --arg01 --arg02 \
1> /home/user_name/projects/dummy_folder_00/log.txt 2>&1 ;

and test again, it should log STDOUT and STDERR to that file then.

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